Variable flow restrictor



Aug. 2s, 1947. E, D, VQPLATQN 2,426,238

VARIABLE FLow nsnxc'ron Filed umh 1 0. 194s 0 /qlji 'f I l .Z i a BY 'Y #rra/ffm Patented Aug. 26, 1947 VARIABLE FLOW RESTRICTOR Edmond D. V. Platon, Paris. France, assignor to International Standard Electric Corporation, New York, N. Y., a corporation of Delaware Application March 10, 1943, Serial No. 478,692 In France March 15, 1941 (Cl. 13S-43) 1o claims. 1

This invention is concerned with' improvements in regulating devices for refrigerating circuits and particularly for improvements in output restrictors for such circuits.

In refrigerating installations that operate by means of a refrigerating fluid which passes through a closed circuit under the control of the compressor, it is customary to install in the circuit between the condenser and the evaporator a self-adjusting device that keeps the -drop in pressure practically constant during operation while permitting automatic balancing of the pressure in the circuit during stand still periods so as to facilitate the starting of the compressor motor when again set in operation. Regulators or restrictors of this kind usually consist of a member having a capillary passage which brings about a drop in pressure of the fluid when it is traversed. l

Pressure regulators of this kind have certain drawbacks, the chief one being the ease with which they are stopped up by impurities which' are frequently present in the refrigerating iluid such as solid particles, traces of lubricant, bits of ice, and the like. Another drawback of capillary devices of this type consists in it being for all practical purposes almost impossible to properly regulate their action since capillary passages are poorly adapted `to accurate adjustments that have todo with effective change in their cross section. Furthermore, capillary channel restrictors find their best use only in low power installations and at refrigerating temperatures approximating zero degrees.

Consequently it is an object of this invention to provide a pressure regulator or restrictor for refrigerating circuits which does not suffer from the above mentioned drawbacks, and is capable of use not only in small units such as household refrigerators, but also in larger installations operating at relatively low temperatures of aboutl minus degrees or less.

`In general the regulator of this invention lcom- .'prises essentially a cylindrical chamber within which space transverse partitions are disposed in 'such a way as to alternately provide narrow an- `nular,passages having a sectionl that increases progressively in the direction of passage of the fluid" and" of pressure relief chambersA between th'ese passages,V These variations of section balancezth" subcessive expansions of uid in the chambers formed between the partitions. Indeed, each passagepofthe fluid subjects it to losses of pressure resultingfrom friction and-the widening and narrowing of the passage section.

More speciiically, a restrictor that embodies the features of this invention comprises essentially a cylindrical chamber within which there is arranged a plurality of spaced transverse partitions having central perforations( of the same diameter. A tapered sh'aft passes through these periorations so that the space between the shaft and the successive partitions constitute the annular passage of sections of progressively increasing size in the direction of travel of the refrigerating uid. y V

In accordance with another feature of this invention means are provided for adjusting the longitudinal position of the tapered shaft with respect to the partitions 'to regulate the eiective area of the passages or perforations in th'e partitions. 1

Another feature of this invention is Athat of providing means for previously cooling the refrigerating fluid before it enters'the restrictor by means of the lower temperature of the restrictor itself. u Further and more detailed objects of the invention will be apparent from the following description of several embodiments thereof selected for illustration in the drawings.

In the accompanying drawings, Figure 1 is a' longitudinal, cross-sectional view through a simpler form of the regulator of this invention;

Figure 2 is a similar view of a modified form u in which the refrigerating iiuid is cooled previous to its passage through the restrictor proper;

and

Figure 3 is a similar view of another modification employing the features of Figure 2 and in addition showing an adjustable structure for longitudinally positioning the tapered shaft.

The restrictor illustrated in Figure 1 comprises a cylindrical housing or body member I, which is closed at one end and provided with a threaded extension 2 having a passage therethrough. The other end of the housing I is closed by a threaded plug which has an externally threaded extension 3 and a passage therethrough. The extensions 2 and 3 provide means for attaching the restrictor into a refrigerating circuit. Disposed within the conned space thus formed are a series of transverse washers 4 forming partitions each having The terminal shown in Figure 1, this shaft has cylindrical dowels at the end which fit snugly in the central openings of the washers. I and 8 to mount the shaft II centrally ofi the, passages 5. The shaft dowels are tightly fitting in the holes in these washers to form fluidtight connections. The washers 'I and 8 also have eccentrically positioned passages 9 and I0 respectively, 'as shown. It will be seen that because shaft II is tapered the effective or free areas of the passages 5 are of increasing size progressively from right .to left, in Figure 1. The refrigerating fluid passes through this device from right to left as indicated by the arrows.

In the operation of this device the refrigerating uid moves through the passage in the plug 3 and through the openings 9 into the space between the washer 1 and the succeeding washer. The fluid therefore undergoes an expansion in this chamber, after which it passes through the annular opening between the end washers and the shaft II into the second chamber where it again expands. 'I'his action continues until the fluid moves through the passages I and out of the restrlctor through the passage in the threaded member' 2. On account of the progressive increase in the size of the passages through the partitions from one chamber to the next the successiveexpansions of the fluid are balanced and the restrictor plays the part of a balanced pressure relief for the refrigerating circuit. The annular sections provided in a restrlctor of this kind possess the advantage over the conventional type of capillary sections that it is difficult for them to become blocked by the various impurities in the refrigerating fluid.

In a refrigerating circuit it is preferable to effect a preliminary cooling of the refrigerating fluid on its way to the restrlctor from the condenser in order that the difference of the thermal potentials between the outletl of the condenser andthe inlet of the evaporator may be increased on account of the greater difference of temperatures. In accordance with this invention this preliminary cooling may be effected within the restrlctor itself by means and arrangements such as shown in' Figure 2.v

In the arrangement of Figure 2 the cylindrical housing I previously described is incorporated in and if desired as a Unitthereof, of an outer housing I3 as shown in Figure 2. The outer housing Y f in this case is closed by a threaded plug as shown,

which has an externally threaded extension 3 as before with a passage through it. Within the plug is a chamber or passage- I4 which is open to the inside of the housing I3 through the longitudinal passages I5. In this case the inner housing I is closed by a screw plug I I having a r central passage. The. interior construction within the housing I is the 'same as that in Figure 1.

Surrounding the inner housing is a wall or partition member I 8 which in the form illustrated will be cylindrical, which is seated in a. complementarily shaped recess in the plug so that the passages I are exterior of the partition I8. The inner housing I terminates in spaced relation to the threaded plug so that fluid may move through the passage in the plug I'I, as indicated by the arrow.

4In the operation of .this device the refrigerating fluid takes the path indicated -by the arrows in Figure 2, entering the chamber I 4 through the passage in the threaded extension 3 and moving from this chamber through the passages I5 to the space within the housing Il around the partltion I6 and then passes into the space between this partition and the housing I, flowing back countercurrent to and through the passage in plug I1. It then traverses the restrictor proper in a manner previously described and exits through the passage inthe threaded extension 2.

In the operation of this device the repeated expansions' of the refrigerating fluid within the restrlctor housing I results in a cooling of the refrigerating fluid. The work done in effecting this expansion is absorbed, from the following incoming fluidas it flows in heat exchange relation with the housing I, which relation is improved by means Iof the partition I6. Thus the temperaturev of the refrigerating fluid is lowered to increase its potential at the point of delivery to the evaporator. It will, of course, be apparent that the partition I6 could be eliminated if desired, and that other forms of defiectors or partitions could be employed to accomplish the object of the partition I6.

In the modification of Figure 3 means is provided for adjusting the restrictive action of the device. In this modification the construction is basically similar to that of Figure 2. However, the housing I 3 is provided with a laterally threaded extension 26 having a passage there- -through, as shown. The end of the housing I3 is closed by a threaded plug 30 and the shaft II has a cylindrical extension I 9 which passes through the plug 30 and the threaded boss 22 mounted thereon. The end I9 of the shaft II is provided with a reduced threaded stud 20 upon which a threaded cap 24 is secured by means of the nut 25. The threaded cap 24 engages the threaded extension .22 so that when the cap is rotated it will advance and retract the shaft II longitudinally. A suitable stuiiing box or packing structure 23 may be employed to prevent leakage of the refrigerating fluid around the shaft. The shaft II is further modified in that its left hand end is provided with a cylindrical extension which may have sliding movement in the central opening in the terminal washer 8. Likewise the terminal washer 1 has a central openingwhich is a sliding llt With the cylindrical portion of the shaft I9. In this case the partition I6 is mounted on the inner face of the plug 30, as shown.

The refrigerating fluid enters the chamber I3 through the passage in the threaded extension 26, flows along the outer face of the partition I6, and back along the inner` face in heat exchange relation with the inner housing I, Then passes through the opening in the plug I 1 and then progresses through the restrlctor as before and out through the passage in the threaded extension 2. It will be seen that by rotating the cap- 24 the longitudinal position of the tapered portion of the shaft II can be changed with respect to the central passages 5 of the washers, and thus the effective area thereof can be varied. As the shaft II is moved to the left these passages are restricted while if it is moved to the right they are enlarged. Thus the restricting action of the regulator can be adjusted as required. It is, of course, apparent that in the structure of Figure 3 the pre-cooling feature of the structure of' Figure 2 is included.

, It is evident that numerous modiiicationsand adaptations can be made in the devices as described Without departure from the scope of the invention. For example, the annular passages of progressively increasing section may be formed by suitable holes drilled in the washers or cutouts in their periphery which will leave semiannular passages, thereby dispensing with the axially perforated washers and the tapered shaft. In the case of holes they would be of progressively increasing diameter and lie within the periphery of the washers. In the caseof the cutouts they would be at their periphery and could be of progressively increasing size. AThey would then be formed in part by the washers and by ,the inner face of the housing I. Of course, the washers 8 would need to be suitably modified. The geometrical form of the restrictive passages can, of course, be changed as desired. They may be polygonal, oval, or of `elliptical form as well as cylindrical.

In addition to the above mentioned arrangements for the primary cooling of the refrigerating fluid, it is to be understood that numerous e other designs may be used for circulating the 4 ,fluid along the cold wall of the expansion chambers of the restrictor. y

It is to be further understood that the principal arrangements of the invention do not require association of the preliminary cooling feature with the adjustment of the passage sections as shown in Figure 3. In other words, this adjustment may be provided independently cf the preliminary cooling feature, asvfor example 4it could be included-in the structure of Figure 1.

Numerous other modifications for effecting adjustment of the effective areas of the passages i may be provided in devices that otherwise incorporate the features of this invention. For example, in the case of adjustment by axial displacement yof the tapered shaft this shaft could be extended so as to only penetrate for a certain distance in the axial perforation of the plug hav-y ing the extension 3. In this case the end of the shaft would be lscrew threaded. In this event the screw cap 24 of the stufling box could then be completely closed and removed for adjustment of the shaft by means, for example, of the screw driver for the receipt ofwhich the end of the shaft would be properly formed. This would insure a tighter joint at the stuiling box during the operation of the device. y

Since it is obvious that many modificationscan be effected by those skilled'in the art, I do not desire to be limited to the examples given herein for illustrative purposes, but rather by the scope of the claims granted me.

What is claimed is:

1. A pressure regulator as described comprising a closed housing, means within said housing forming a plurality of chambers connected in series by restricted passages of progressively increasing area, and means surrounding said housL ing to form an elongated passage, a portion of which is formed by the exterior wall of said housing, said elongated passage connecting with an intake opening and with the chambers at' the entry side of the chamber assembly. l

2. In the combination of claim 1, said means comprising a plurality of transverse partitions having passages therethrough and a tapered shaft lying in said passages.

3. A pressure regulator as described comprising a closed housing having anentering and exit passage, means within the housing forming a plurality of chambers connected in series byl restricted passages of 'progressively increasing area, said means consisting of a plurality of transverse partitioning washers and interposed spacing washers clamped in pressure sealing engagement and means for adjusting the effective area of said restricted passages.

4.-A pressure regulator as claimed in claim 3 wherein-the partitioning washers have Vaxially positioned passages therethrough of uniform diameter and a tapered'shaft extends through said passages and is adjustably supported for axial movement to vary the effective area of the restricted passages.

5. A pressure regulator of the character described comprising a housing member having opposite end walls, at least one of which is separable with threaded engagement with the housing for longitudinal adjustment. said housing being provided with entry and exit passages, means within the housing for forming a plurality of expansion chambers consisting of a series of l scribed lcomprising a housing member having opposite end walls, at least one of which is separable with threaded engagement with the housing member for longitudinal adjustment, said housing being provided with entry and exit passages, means within the housing for forming a plurality of expansion chambers consisting of a series of separable partitioning washers, having interposed spacing washers and clamped in pressure sealing engagement by the adjustable end wall, the end-most of the partitioning washers having central bearing apertures, a tapered shaft having bearing support in the bearing apertures and the intermediate washers having central apertures of uniform diameter in spaced relation tothe shaft to provide restricted. passages between the chambers of progressively increasing area and said end washers having outwardly positioned entry and exit openings respectively.

'7. A pressure regulator of the character'described comprising a housing composed of a body having opposite end walls. at least one of which is separable with threaded engagement with the body for longitudinal'adjustment, said housing being provided with entry and exit passages,

means Within the housing forming a plurality A of expansion chambers consisting of a series of separable partitioning washers having inter- Iposedspacing washers and clamped in pressure sealing engagement by the adjustable end wall,

at least the intermediate of said partitioning washers being formed with central apertures of uniform diameter, a tapered shaft supported to extend through said apertures to provide restricted passages of progressively increasing area between the chambers and said housing being formed with an entry connecting passage surrounding the expansion chambers to effect an initial cooling of the gases in their passage to the exit opening.

8. A` pressure regulator of the character specified comprising a closed housing having inlet means at one end and outlet means at the other end, means in said housing for providing a series of chambers separated by transverse partitions and connected by coaxial apertures in said partitions, and a shaft extending through said co- 7 axial apertures and coaxial therewith, the areas of said apertures andthe cross-sections of the corresponding portions of the shaft determining annular passages increasing progressively in area from the inlet to the outlet.

9. A pressure regulator of the character described comprising a. closed housing having inlet means at one end and outlet means at the other end, means including transverse partitions with coaxial apertures of the same area for provid- 1 ,10; A pressure regulator as claimed in claim 9 wherein the position of the shaft may be varied longitudinally thereof to vary the areas of the restricted annular passages.

EDMOND V. PLATON.

REFERENCES CITED The following references are of record in the 0 file of this patent:

UNITED STATES PATENTS Number Name Date .2,187,662 Pigott Jan. 16, 1940 15 1,766,554 Lieber June 24, 1930 2,162,842 Dolison et al June 30, 1939 

